Health In Focus
  • Study by UCL researchers details the effect of cannabis on motivation to work for money.
  • Lowered motivation level is a short term effect of the drug.
  • There was no long term effect on motivation due to the drug.

A study published in the Journal Psychopharmacology details the influence of cannabis on the motivation levels of people. It is widely believed that cannabis could make people lazy but there has never been a scientific study to understand the influence of this drug on motivation.

Scientists from The University College London carried out two studies to understand the effect of cannabis use on the motivation level of people.
Weed Could Snuff Out Motivation, Reveals Study on Cannabis


Cannabis is the generic name for the plant Cannabis sativa. This crop is grown widely and transported illegally across countries due to its psychoactive agents that are meant to give an individual a 'high'.
  • It is a widely used substance across the world.
  • 2.3 million people in the U.K use cannabis between 16 to 59 years of age.
  • It is also known as marijuana, hashish, weed or pot.
  • The drug is used to relax and to get a 'high'
  • Certain forms of the drug are found to be stronger than certain others.
  • The use of cannabis can lead to addiction and is considered illegal in many countries.
The effects of cannabis and its influence on people are commonly known but it has never been scientifically documented. This psychotropic drug is known to make a person feel light, with an increase in response to colors and music. Most importantly, it is believed to bring in a sense of lethargy and an inhibition towards carrying any physical endurance test.

Scientists from The University College London decided to check this belief by carrying out a couple of tests that were aimed at understanding the effect of cannabis on short-term motivation and long-term motivation to earn money.

Dr. Will Lawn who is the lead author of the study and from The University College London's Department of Clinical Psychopharmacology says "Although cannabis is commonly thought to reduce motivation, this is the first time it has been reliably tested and quantified using an appropriate sample size and methodology. It has also been proposed that long-term cannabis users might also have problems with motivation even when they are not high. However, we compared people dependent on cannabis to similar controls, when neither group was intoxicated, and did not find a difference in motivation. This tentatively suggests that long-term cannabis use may not result in residual motivation problems when people stop using it. However, longitudinal research is needed to provide more conclusive evidence."

Cannabis and the Motivation Studies

There were two studies that were conducted to assess the motivation to work for money among cannabis users.

Short Term Motivation Study

17 adult volunteers who used cannabis occasionally were included in the study. They were made to inhale cannabis through a balloon on a particular occasion and at another occasion they were made to inhale a placebo vapor through a balloon.

These occasional users of cannabis were then tested to record their level of motivation for money.

The Task

The volunteers were made to tap the spacebar with their little finger and were given monetary rewards depending upon the number of times they tapped.
  • 50p when the spacebar was tapped 30 times in 7 seconds.
  • 80p to 2 when the space bar is tapped up to 100 times in 21 seconds
Dr Professor Val Curran who is the senior author and professor of clinical psychopharmacology at UCL had this to say about the tasks that were administered "Repeatedly pressing keys with a single finger isn't difficult but it takes a reasonable amount of effort, making it a useful test of motivation. We found that people on cannabis were significantly less likely to choose the high-effort option. On average, volunteers on placebo chose the high-effort option 50% of the time for a 2 reward, whereas volunteers on cannabis only chose the high-effort option 42% of the time."

Long Term Motivation Study

This part of the study focused on assessing the motivation level of cannabis users extended over a period of time. 20 people who were addicted to cannabis use were included in the study while 20 non-drug users were taken as the control group. To assess for long term motivation, the study group was asked not to drink alcohol or drugs for 12 hours before the study while they were allowed to use tobacco or coffee.

The study participants and the control group were made to perform the earlier task of tapping on the spacebar. The study found no significant difference in the motivation to work for money in both the study group as well as the control group.

The study shows that the use of cannabis could induce feelings of lethargy and the individual may be unable to perform a task even when offered a reward of money. This could signal the significant damage that the use of this drug could unleash on people, forcing them into a stupor that prevents them from working harder to earn better. The long term effects of the drug did not have any effect on the need to work harder for money, but larger studies may be required to fully establish the de-motivational effects of this drug.

References :
  1. Cannabis and Mental Health - (
  2. Cannabis General Information - (
Source: Medindia

Most Popular on Medindia